1. Field of Endeavor
The present disclosure relates to a method and system for detecting error of auto focus calibration.
2. Background
This section provides background information related to the present disclosure which is not necessarily prior art.
Generally, a camera module includes a lens barrel including a lens, a housing assembly coupled to the lens barrel, a sensor unit including an IR (Infrared) filter and an image sensor.
In a case the camera module mounted with an actuator moves the lens barrel to perform an AF (Auto Focusing), a best focusing position is sought after by moving the lens from an infinity to macro.
However, a best-focused lens position at a same distance may vary due to lens deviation of each camera module, deviation in dynamic characteristic of an actuator, tilt and rotation deviations possibly generated in assembly.
Thus, an autofocus calibration is performed where a code corresponding to a best focus lens position for infinity and macro for each camera module is stored in a memory of the camera module.
Referring to FIG. 1, a mobile terminal mounted with a camera module generally performs an autofocus search between an infinity autofocus calibration code and a macro autofocus calibration code stored in the memory of the camera module. At this time, as shown in FIG. 2, a collimator lens (30) is interposed between a resolution chart (10) and a camera module (20) to measure a real distance in a case an infinity autofocus calibration is performed.
However, an error may occur where an infinity autofocus calibration is performed at a position different from a real infinity due to deviation in a collimator lens and erroneous operation.
In a case a code is stored in a memory that is larger than a real infinity best focus code, the mobile terminal is changed in auto focus search section, a focus of an object in infinity and a focus of an object in a position in a particular distance cannot be disadvantageously captured.